var kDom = document.getElementById('k');
var buttonDom = document.getElementById('button');
 buttonDom.onclick =  function change(){
   	kDom.style.transition = '0.8s';
   	if(kDom.style.transform == 'rotate(0deg)'){
   		kDom.style.transform = 'rotate(720deg)';
   	}else{
   		kDom.style.transform = 'rotate(0deg)';
   	}
   }
//buttonDom.onclick = setInterval(change,80);